6.
a. Mother’s genotype: IAIA or IAi
b. Father’s genotype: IBIB or IBi
c. Baby’s genotype: IAIB
d. Punnett square that shows the baby’s genotype as a possibility:
- If mother is IAIA and father is IBIB: all offspring are IAIB (Type AB).
- If mother is IAIA and father is IBi: 50% IAIB, 50% IAi.
- If mother is IAi and father is IBIB: 50% IAIB, 50% IBi.
- If mother is IAi and father is IBi: 25% IAIB, 25% IAi, 25% IBi, 25% ii.
e. Could the baby actually be theirs? Yes.
7.
The mailman could not be the father of the baby.
8.
The baby was taken away by the state because none of the potential fathers could have produced a Type AB baby with a Type O mother. A Type O mother has genotype ii and can only pass an i allele. A Type AB baby has genotype IAIB, requiring one IA and one IB allele from the parents. Since the mother can only contribute i, it is genetically impossible for her to have a Type AB child with any of the listed men.
Parent Tip: Review the logic above to help your child master the concept of codominance worksheet blood types.
